Pane
Extended

A container for presenting content in the center of the workspace.
Panes can contain multiple items, one of which is active at a given time.
The view corresponding to the active item is displayed in the interface. In
the default configuration, tabs are also displayed for each item.

Each pane may also contain one pending item. When a pending item is added
to a pane, it will replace the currently pending item, if any, instead of
simply being added. In the default configuration, the text in the tab for
pending items is shown in italics.

Invoke the given callback when ::moveActiveItemToTopOfStack
has been called, terminating an MRU traversal of pane items and moving the
current active item to the top of the stack. Typically bound to a modifier
(e.g. CTRL) key up event.